1. Field of the Invention
The present invention pertains to the art of cooking appliances and, more particularly, to an airflow system designed to eliminate potential moisture condensation associated with operation of a microwave cooking appliance.
2. Discussion of the Prior Art
During a typical cooking operation, a food item is placed into an oven cavity to be subjected to cooking temperatures. The cooking temperatures cause moisture contained in food items to be released into the oven cavity. This is particularly true in the case of microwave cooking. A microwave cooking operation is performed by directing microwave energy fields into an oven cavity, with the energy fields reflecting about and impinging upon a food item. As the microwave energy fields impinge upon the food item, the energy fields are converted into heat through two mechanisms. The first or ionic mechanism is caused by the linear acceleration of ions, generally in the form of salts present within the food item. The second is the molecular excitation of polar molecules, primarily water, present within the food item.
The excitation of polar molecules causes the water or moisture to be released into the oven cavity. The moisture can either condense within the oven cavity or be carried by air currents circulating in the oven cavity to a point outside the oven cavity. If the air currents are not sufficient enough to carry the moisture from the appliance, the moisture exiting from the oven cavity could condense on ducting or other structure employed to guide the air currents from the appliance. Moisture building up within the ducting or other structure will ultimately find a path that leads from the appliance. Obviously, developed moisture could cause damage to surrounding cabinetry or to control components of the overall appliance. This is particularly true in connection with a double wall oven incorporating control components directly below an oven cavity.
Several attempts to address this problem are found in the prior art. In one example, contained in U.S. Pat. No. 5,945,023, a number of holes are formed in a lower portion of a side wall of an oven cavity. The holes allow moisture to escape from the oven cavity and be directed through a bottom portion of the appliance. In another example proposed in U.S. Pat. No. 4,123,643, a first air current is directed past a magnetron before being introduced into the oven cavity to mix with a second air current. The combined air currents absorb moisture and are then directed out of a front portion of the oven cavity.
Despite the existence of the prior art arrangements, there still exists a need for an airflow system that will carry moisture away from a microwave cooking appliance in a manner that will assure that surrounding structure will not be negatively affected by the moisture. Specifically, there exists a need for an airflow system that will transport moisture laden air outside the oven cavity so that the moisture does not build-up, condense and drip on surrounding cabinetry or other appliance structure.